[PATCH v5 05/10] VAS: Define helpers to init window context

From: Sukadev Bhattiprolu
Date: Thu May 25 2017 - 01:41:19 EST

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Define helpers to initialize window context registers of the VAS
hardware. These will be used in follow-on patches when opening/closing
VAS windows.

Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
---
Changelog[v5]
- Fix: Copy the FIFO address into LFIFO_BAR register as is (don't
shift address into bits 8:53).

Changelog[v4]
- Michael Neuling] Use ilog2(), radix_enabled() helpers;
drop warning when 32-bit app uses VAS (a follow-on patch
will check and return error). Set MSR_PR state to 0 for
kernel (rather than reading from MSR).

Changelog[v3]
- Have caller, rather than init_xlate_regs() reset window regs
so we don't reset any settings caller may already have set.
- Translation mode should be 0x3 (0b11) not 0x11.
- Skip initilaizing read-only registers NX_UTIL and NX_UTIL_SE
- Skip initializing adder registers from UWC - they are already
initialized from the HVWC.
- Check winctx->user_win when setting translation registers
---
arch/powerpc/platforms/powernv/vas-window.c | 306 ++++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/vas.h | 55 +++++
2 files changed, 361 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 588aad7..4135ab0 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -11,9 +11,12 @@
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/io.h>
+#include <linux/log2.h>

#include "vas.h"

+static int fault_winid;
+
/*
* Compute the paste address region for the window @window using the
* ->paste_base_addr and ->paste_win_id_shift we got from device tree.
@@ -138,6 +141,309 @@ int map_winctx_mmio_bars(struct vas_window *window)
return 0;
}

+/*
+ * Reset all valid registers in the HV and OS/User Window Contexts for
+ * the window identified by @window.
+ *
+ * NOTE: We cannot really use a for loop to reset window context. Not all
+ * offsets in a window context are valid registers and the valid
+ * registers are not sequential. And, we can only write to offsets
+ * with valid registers (or is that only in Simics?).
+ */
+void reset_window_regs(struct vas_window *window)
+{
+ write_hvwc_reg(window, VREG(LPID), 0ULL);
+ write_hvwc_reg(window, VREG(PID), 0ULL);
+ write_hvwc_reg(window, VREG(XLATE_MSR), 0ULL);
+ write_hvwc_reg(window, VREG(XLATE_LPCR), 0ULL);
+ write_hvwc_reg(window, VREG(XLATE_CTL), 0ULL);
+ write_hvwc_reg(window, VREG(AMR), 0ULL);
+ write_hvwc_reg(window, VREG(SEIDR), 0ULL);
+ write_hvwc_reg(window, VREG(FAULT_TX_WIN), 0ULL);
+ write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
+ write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), 0ULL);
+ write_hvwc_reg(window, VREG(PSWID), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE1), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE2), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE3), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE4), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE5), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE6), 0ULL);
+ write_hvwc_reg(window, VREG(LFIFO_BAR), 0ULL);
+ write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), 0ULL);
+ write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), 0ULL);
+ write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
+ write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
+ write_hvwc_reg(window, VREG(LRX_WCRED), 0ULL);
+ write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
+ write_hvwc_reg(window, VREG(TX_WCRED), 0ULL);
+ write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
+ write_hvwc_reg(window, VREG(LFIFO_SIZE), 0ULL);
+ write_hvwc_reg(window, VREG(WINCTL), 0ULL);
+ write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
+ write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), 0ULL);
+ write_hvwc_reg(window, VREG(TX_RSVD_BUF_COUNT), 0ULL);
+ write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_CTL), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_PID), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_LPID), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_TID), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), 0ULL);
+ write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
+
+ /* Skip read-only registers: NX_UTIL and NX_UTIL_SE */
+
+ /*
+ * The send and receive window credit adder registers are also
+ * accessible from HVWC and have been initialized above. We don't
+ * need to initialize from the OS/User Window Context, so skip
+ * following calls:
+ *
+ * write_uwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
+ * write_uwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
+ */
+}
+
+/*
+ * Initialize window context registers related to Address Translation.
+ * These registers are common to send/receive windows although they
+ * differ for user/kernel windows. As we resolve the TODOs we may
+ * want to add fields to vas_winctx and move the initialization to
+ * init_vas_winctx_regs().
+ */
+static void init_xlate_regs(struct vas_window *window, bool user_win)
+{
+ uint64_t lpcr, val;
+
+ /*
+ * MSR_TA, MSR_US are false for both kernel and user.
+ * MSR_DR and MSR_PR are false for kernel.
+ */
+ val = 0ULL;
+ val = SET_FIELD(VAS_XLATE_MSR_HV, val, true);
+ val = SET_FIELD(VAS_XLATE_MSR_SF, val, true);
+ if (user_win) {
+ val = SET_FIELD(VAS_XLATE_MSR_DR, val, true);
+ val = SET_FIELD(VAS_XLATE_MSR_PR, val, true);
+ }
+ write_hvwc_reg(window, VREG(XLATE_MSR), val);
+
+ lpcr = mfspr(SPRN_LPCR);
+ val = 0ULL;
+ /*
+ * NOTE: From Section 5.7.6.1 Segment Lookaside Buffer of the
+ * Power ISA, v2.07, Page size encoding is 0 = 4KB, 5 = 64KB.
+ *
+ * NOTE: From Section 1.3.1, Address Translation Context of the
+ * Nest MMU Workbook, LPCR_SC should be 0 for Power9.
+ */
+ val = SET_FIELD(VAS_XLATE_LPCR_PAGE_SIZE, val, 5);
+ val = SET_FIELD(VAS_XLATE_LPCR_ISL, val, lpcr & LPCR_ISL);
+ val = SET_FIELD(VAS_XLATE_LPCR_TC, val, lpcr & LPCR_TC);
+ val = SET_FIELD(VAS_XLATE_LPCR_SC, val, 0);
+ write_hvwc_reg(window, VREG(XLATE_LPCR), val);
+
+ /*
+ * Section 1.3.1 (Address translation Context) of NMMU workbook.
+ * 0b00 Hashed Page Table mode
+ * 0b01 Reserved
+ * 0b10 Radix on HPT
+ * 0b11 Radix on Radix
+ */
+ val = 0ULL;
+ val = SET_FIELD(VAS_XLATE_MODE, val, radix_enabled() ? 3 : 2);
+ write_hvwc_reg(window, VREG(XLATE_CTL), val);
+
+ /*
+ * TODO: Can we mfspr(AMR) even for user windows?
+ */
+ val = 0ULL;
+ val = SET_FIELD(VAS_AMR, val, mfspr(SPRN_AMR));
+ write_hvwc_reg(window, VREG(AMR), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_SEIDR, val, 0);
+ write_hvwc_reg(window, VREG(SEIDR), val);
+}
+
+/*
+ * Initialize Reserved Send Buffer Count for the send window. It involves
+ * writing to the register, reading it back to confirm that the hardware
+ * has enough buffers to reserve. See section 1.3.1.2.1 of VAS workbook.
+ *
+ * Since we can only make a best-effort attempt to fulfill the request,
+ * we don't return any errors if we cannot.
+ *
+ * TODO: Reserved (aka dedicated) send buffers are not supported yet.
+ */
+static void init_rsvd_tx_buf_count(struct vas_window *txwin,
+ struct vas_winctx *winctx)
+{
+ write_hvwc_reg(txwin, VREG(TX_RSVD_BUF_COUNT), 0ULL);
+}
+
+/*
+ * init_winctx_regs()
+ * Initialize window context registers for a receive window.
+ * Except for caching control and marking window open, the registers
+ * are initialized in the order listed in Section 3.1.4 (Window Context
+ * Cache Register Details) of the VAS workbook although they don't need
+ * to be.
+ *
+ * Design note: For NX receive windows, NX allocates the FIFO buffer in OPAL
+ * (so that it can get a large contiguous area) and passes that buffer
+ * to kernel via device tree. We now write that buffer address to the
+ * FIFO BAR. Would it make sense to do this all in OPAL? i.e have OPAL
+ * write the per-chip RX FIFO addresses to the windows during boot-up
+ * as a one-time task? That could work for NX but what about other
+ * receivers? Let the receivers tell us the rx-fifo buffers for now.
+ */
+int init_winctx_regs(struct vas_window *window, struct vas_winctx *winctx)
+{
+ uint64_t val;
+ int fifo_size;
+
+ reset_window_regs(window);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LPID, val, winctx->lpid);
+ write_hvwc_reg(window, VREG(LPID), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_PID_ID, val, winctx->pidr);
+ write_hvwc_reg(window, VREG(PID), val);
+
+ init_xlate_regs(window, winctx->user_win);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_FAULT_TX_WIN, val, fault_winid);
+ write_hvwc_reg(window, VREG(FAULT_TX_WIN), val);
+
+ /* In PowerNV, interrupts go to HV. */
+ write_hvwc_reg(window, VREG(OSU_INTR_SRC_RA), 0ULL);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_HV_INTR_SRC_RA, val, winctx->irq_port);
+ write_hvwc_reg(window, VREG(HV_INTR_SRC_RA), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_PSWID_EA_HANDLE, val, winctx->pswid);
+ write_hvwc_reg(window, VREG(PSWID), val);
+
+ write_hvwc_reg(window, VREG(SPARE1), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE2), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE3), 0ULL);
+
+ /*
+ * NOTE: VAS expects the FIFO address to be copied into the LFIFO_BAR
+ * register as is - do NOT shift the address into VAS_LFIFO_BAR
+ * bit fields! Ok to set the page migration select fields -
+ * VAS ignores the lower 10+ bits in the address anyway, because
+ * the minimum FIFO size is 1K?
+ *
+ * See also: Design note in function header.
+ */
+ val = __pa(winctx->rx_fifo);
+ val = SET_FIELD(VAS_PAGE_MIGRATION_SELECT, val, 0);
+ write_hvwc_reg(window, VREG(LFIFO_BAR), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LDATA_STAMP, val, winctx->data_stamp);
+ write_hvwc_reg(window, VREG(LDATA_STAMP_CTL), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LDMA_TYPE, val, winctx->dma_type);
+ write_hvwc_reg(window, VREG(LDMA_CACHE_CTL), val);
+
+ write_hvwc_reg(window, VREG(LRFIFO_PUSH), 0ULL);
+ write_hvwc_reg(window, VREG(CURR_MSG_COUNT), 0ULL);
+ write_hvwc_reg(window, VREG(LNOTIFY_AFTER_COUNT), 0ULL);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LRX_WCRED, val, winctx->wcreds_max);
+ write_hvwc_reg(window, VREG(LRX_WCRED), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_TX_WCRED, val, winctx->wcreds_max);
+ write_hvwc_reg(window, VREG(TX_WCRED), val);
+
+ write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), 0ULL);
+ write_hvwc_reg(window, VREG(TX_WCRED_ADDER), 0ULL);
+
+ fifo_size = winctx->rx_fifo_size / 1024;
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LFIFO_SIZE, val, ilog2(fifo_size));
+ write_hvwc_reg(window, VREG(LFIFO_SIZE), val);
+
+ /* Update window control and caching control registers last so
+ * we mark the window open only after fully initializing it and
+ * pushing context to cache.
+ */
+
+ write_hvwc_reg(window, VREG(WIN_STATUS), 0ULL);
+
+ init_rsvd_tx_buf_count(window, winctx);
+
+ /* for a send window, point to the matching receive window */
+ val = 0ULL;
+ val = SET_FIELD(VAS_LRX_WIN_ID, val, winctx->rx_win_id);
+ write_hvwc_reg(window, VREG(LRFIFO_WIN_PTR), val);
+
+ write_hvwc_reg(window, VREG(SPARE4), 0ULL);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_NOTIFY_DISABLE, val, winctx->notify_disable);
+ val = SET_FIELD(VAS_INTR_DISABLE, val, winctx->intr_disable);
+ val = SET_FIELD(VAS_NOTIFY_EARLY, val, winctx->notify_early);
+ val = SET_FIELD(VAS_NOTIFY_OSU_INTR, val, winctx->notify_os_intr_reg);
+ write_hvwc_reg(window, VREG(LNOTIFY_CTL), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LNOTIFY_PID, val, winctx->lnotify_pid);
+ write_hvwc_reg(window, VREG(LNOTIFY_PID), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LNOTIFY_LPID, val, winctx->lnotify_lpid);
+ write_hvwc_reg(window, VREG(LNOTIFY_LPID), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LNOTIFY_TID, val, winctx->lnotify_tid);
+ write_hvwc_reg(window, VREG(LNOTIFY_TID), val);
+
+ val = 0ULL;
+ val = SET_FIELD(VAS_LNOTIFY_MIN_SCOPE, val, winctx->min_scope);
+ val = SET_FIELD(VAS_LNOTIFY_MAX_SCOPE, val, winctx->max_scope);
+ write_hvwc_reg(window, VREG(LNOTIFY_SCOPE), val);
+
+ /* Skip read-only registers NX_UTIL and NX_UTIL_SE */
+
+ write_hvwc_reg(window, VREG(SPARE5), 0ULL);
+ write_hvwc_reg(window, VREG(NX_UTIL_ADDER), 0ULL);
+ write_hvwc_reg(window, VREG(SPARE6), 0ULL);
+
+ /* Finally, push window context to memory and... */
+ val = 0ULL;
+ val = SET_FIELD(VAS_PUSH_TO_MEM, val, 1);
+ write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), val);
+
+ /* ... mark the window open for business */
+ val = 0ULL;
+ val = SET_FIELD(VAS_WINCTL_REJ_NO_CREDIT, val, winctx->rej_no_credit);
+ val = SET_FIELD(VAS_WINCTL_PIN, val, winctx->pin_win);
+ val = SET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val, winctx->tx_wcred_mode);
+ val = SET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val, winctx->rx_wcred_mode);
+ val = SET_FIELD(VAS_WINCTL_TX_WORD_MODE, val, winctx->tx_word_mode);
+ val = SET_FIELD(VAS_WINCTL_RX_WORD_MODE, val, winctx->rx_word_mode);
+ val = SET_FIELD(VAS_WINCTL_FAULT_WIN, val, winctx->fault_win);
+ val = SET_FIELD(VAS_WINCTL_NX_WIN, val, winctx->nx_win);
+ val = SET_FIELD(VAS_WINCTL_OPEN, val, 1);
+ write_hvwc_reg(window, VREG(WINCTL), val);
+
+ return 0;
+}
+
/* stub for now */
int vas_win_close(struct vas_window *window)
{
diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h
index 12c6380..895bdec 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -12,6 +12,7 @@
#include <linux/atomic.h>
#include <linux/idr.h>
#include <asm/vas.h>
+#include <linux/io.h>

/*
* Overview of Virtual Accelerator Switchboard (VAS).
@@ -382,4 +383,58 @@ struct vas_winctx {
extern bool vas_initialized(void);
extern struct vas_instance *find_vas_instance(int vasid);

+/*
+ * VREG(x):
+ * Expand a register's short name (eg: LPID) into two parameters:
+ * - the register's short name in string form ("LPID"), and
+ * - the name of the macro (eg: VAS_LPID_OFFSET), defining the
+ * register's offset in the window context
+ */
+#define VREG_SFX(n, s) __stringify(n), VAS_##n##s
+#define VREG(r) VREG_SFX(r, _OFFSET)
+
+#ifndef vas_debug
+static inline void vas_log_write(struct vas_window *win, char *name,
+ void *regptr, uint64_t val)
+{
+ if (val)
+ pr_err("%swin #%d: %s reg %p, val 0x%016llx\n",
+ win->tx_win ? "Tx" : "Rx", win->winid, name,
+ regptr, val);
+}
+
+#else /* vas_debug */
+
+#define vas_log_write(win, name, reg, val)
+
+#endif /* vas_debug */
+
+static inline void write_uwc_reg(struct vas_window *win, char *name,
+ int32_t reg, uint64_t val)
+{
+ void *regptr;
+
+ regptr = win->uwc_map + reg;
+ vas_log_write(win, name, regptr, val);
+
+ out_be64(regptr, val);
+}
+
+static inline void write_hvwc_reg(struct vas_window *win, char *name,
+ int32_t reg, uint64_t val)
+{
+ void *regptr;
+
+ regptr = win->hvwc_map + reg;
+ vas_log_write(win, name, regptr, val);
+
+ out_be64(regptr, val);
+}
+
+static inline uint64_t read_hvwc_reg(struct vas_window *win,
+ char *name __maybe_unused, int32_t reg)
+{
+ return in_be64(win->hvwc_map+reg);
+}
+
#endif /* _VAS_H */
--
2.7.4

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